Kate Simpson Hayes (née, Hayes; after first marriage, Simpson; after separation, Hayes; pen names, Mary Markwell, Elaine, Marka Wohl, Yukon Bill; 6 July 1856 - 15 January 1945) was a Canadian playwright, author, journalist, poet, teacher, milliner, and legislative librarian.

She was a founding member of the Canadian Women's Press Club, and the first woman journalist in Western Canada.

Catherine Ethel Hayes was born in 1856, in Dalhousie, New Brunswick.

[3] She married Charles Bowman Simpson in 2 June 1882; they had two children before separating in 1889.

[2] Kate Simpson Hayes died in Victoria, British Columbia, 15 January 1945.